Adjustable harmonic ringer for selective signaling systems.



No.831,848. Y PATENTED SEPT ;25,1906.'

J. ERICKSON.

ADJUSTABLE HARMONIG RINGER FOB. SELECTIVE SIGNALING SYSTEMS.

APPLICATION FILED SEPT.1B,1905.

' 2 SHEETS-SHEET 1.

WWW/f No. 831,848. 4 PATENTED SEPT. 25; 1906. J. ERICKSON. ADJUSTABLE HARMONIG RINGER FOR SELECTIVE SIGNALING SYSTEMS.

APPLICATION FILED SEPT. 18, 1905.

g I Z SHEETSSHEET 2.

i%. l6 fit 4 I To all whom it may concern:

adapted more particu arly for use in party- En snares PATENT OFFICE.

JOHN ERICKSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC" ELECTRIC COMPANY, OF CHICAGO, ILLINOIS.

ADJUSTABLE HARMONIC RINGER FOR SELECTIVE SIGNALING SYSTEMS.

Specification of Letters Patent.

Patented Sept. 25, 1906.

Application filed September 18, 1905. Serial No. 278.902.

Be it known that I, JOHN ERIOKSON, a citizen of the United States of America, and a resident of Chicago, Cook county, Illinois, have invented a certain new and useful Imroveinent in Adjustable Harmonic Ringers or Selective Signaling Systems, of which the following is a specification.

My invention relates to ringers adapted for use in telephone s stems in' general, but

line telephone systems, and more especial to ringers adapted for use in(party-l1ne systems o crating on the tune or harmonic princip e. In party-line telephone systems it is desirable and of considerable advantage to have the apparatus so constructed that the operator at the exchange or central station can ring the bell at any particular subscribers station on a line Without ringing the bells at any of the other stations on t e line. Party-line systems operating in this manner are ordinarily known as selective systems, inasmuch as the operator can at will ring any one of the bells one line to the exclusion of all the other bells on the same'line, this being much more satisfactory to the subscribers than the old and well-known arrange ment in which several subscribers use the same line, but in which all the bells rin each time any subscriber on the line is called, thus making it-necessary to resort to the expedient of a different number of rings for each subscriber. In some of the' selective party-line systems the signal-receiving means at each subscribers station is of a tuned or harmonic character, while in other selective party-line s stems the said means are of a non-tuned c ar'acter, the tuned and-non-tuned a paratus being dependent, of course, upon di erent principles for the selectivity of tie ringing or signaling of the different subscribers.

My invention, as stated, relates to select ive signaling systems of-the tuned or harmonic characterthat is to say, to selective signaling. or ringing systems-in which each.

ringer or signal-receiving means is so constructed or adjusted that it will only respond to a vibratory or alternating current of a certain period ofvibration orfrequency. In some cases the circuit itself is so constructed or adjusted that it has a certain definite electrical resonance or period of vibration, and is thus made capable of receiving a vibratory or alsame.

ternating current having the same period of vibration or frequency and excluding all others. Again, and in other cases, the ringer or signal-receiving means mayitself be so constructed or adjusted that any vibratory or alternating current will pass through it readily, but in such manner that it will respond only to that current which has a similar period of v1- I brationthat is to sa a period of vibration exactly or substantial y the same as its own. In one case, therefore, the tuning is purely of an electrical character, a circuit being provided which will only respond electrically to currents having the same period of electrical vibration as its own,.while in the other case the tuning is of a mechanical character, so to speak, the mechanical construction of the ringer itself being such that although all currents thrown on the line pass through its windin son'ly that current which has exactly the rig It period of vibration or frequency will-induce a corresponding vibration on the part of its striker. In any event, however, and regardless of the ex edient employed it will be seen that a tune or harmonic select- -ive ringing system utilizes the fundamental ringing as manydifferent bells orringers on .the same line.

Generally stated, the object of my invention is, therefore, the provision of an improved and highly efficient selective ringing or signalin system adapted to operate on the tune or harmonic principle.

'Special objects of my invention are the rovision of, an improved and simplified selective ringing or signaling system of that character in which a plurality of ringers or electric bells are connected in parallel in the same circuit and in which all of the different currents employed for ringing the different bells or ringers pass through al of the bells or ringers with equal facility and in which each .bell or, ringer only responds to its allotted character of current, the provision of an improved construction and arrangement whereby the gongs of the hell or ringer may be readily adjusted toward and away from each other, the provision of an improved construction and arrangementfor holding the gongs firmly in place upon their mountings, the provision of an improved construction and arrangement whereby all of the diil erent' bells or ringers in a selective ringing or signaling system operating on the tuned or harmonic principle may be of the same oonstruction, thus obviating the necessity of manufacturing several different kinds of bells or ringers and making it possible to supply all of the stations on a party-line with the same bration or frequency, the provision of a bell striker can be readily changed or varied by or ringer in which the natural vibration of its simply varying the fulcrum or pivotal point of the striker, and the provision of certain details and features of improvement tending to increase the eneral efficiency and service.- ability of a po arized electric bell or ringer of this particular character.

To the foregoing and other useful ends my invention consists in matters hereinafter set forth and claimed.

ed armature.

' Inthe accompanying drawings, Figure 1 is a conventional diagram illustrating a partyline or selective ringing system embodying the principles of my invention. *Fig. Zis a front elevation of a harmonic bell oiyringer embodying the principles of my invention,

one of the gongs of the same being-shown in section. Fig. 3 1s a top view of the bell or ringer shown in Fig. 2, showing the gongs removed and showing certain portions'of the supporting structure in horizontal section. Fig. 4 is a vertical section on line 1 din Fig. 2. Fig. 5- is a perspective of one of the removable gong posts or mountings. Fig. 6 is a plan of the adjustable fulcrum or pivotal point for the striker, showing adjacent parts in section. view of the connection between the lower end of the gong-striker and the pivotally-mount- F ig. 8 is a detail showing the connection between the top plate or bodyframe. and the upper end of one of the uprights or posts upon which the armatureyoke is mounted.

As thus illustrated, my invention coinprises high and low frequency alternatingcurrent generators A and B, together with a Fig. 7 is a detail perspective senses couple of intermediate-frequency generators C and D, all driven by a suitable motor E. The switchboard-operator is provided'with a selective ringing-key having four push-buttons 1, 2, 3, and 4:. The'push-button l is provided with switch-contacts '11 by which the'generator A can be connected with the line conductors 5 and 6, constituting the party-line. In a similar way the push-button 2 is provided with contacts 0, by which the generator C can be connected with the said line. The ush-button 3 has a set of switch-contacts by which the generator D can be connected with the said party-line, and, finally, the push-button 4 has a set of contacts I), by which the generator B can be connected withth'e said line. In each case the said contacts are normally open, whereby all of said generators are normally discon-' nected from the said line; 4

It will be readily understood that the switchboard-operators equipment may also include suitable plugs and jacks or other switching devices-by which the saidswitchkey can be connected with the said line when it is desired toconnect any one of the said generators therewith. Across the said line are a number of polarized ringers or electric bells F, G, H, and i, the same corresponding in number to the number of ush-buttons in the operators selective ringing-key, and in each case the hell or ringer is bridged across the line-circuit by means of acondenser 7,. there being as many condensers as there arev bells or ringers. It will'also' be understood that these bells or ringers are located at different subscribers stations located along the line and that in each case the subscribers equipment may involve any suitable known or approved devices. With this arrangement the push button 1 can be pressed for ICC the purpose of connecting the-generator A with theline andfor thereby ringing the bell or ringer I, the latter being a high-frequency ringer. 'When the buttonZ is pressed, the generator S is-connec'ted with the line, with the result thatthe hell or ringer-H is rung, the latter being an" intermediate-frequency ringer; If the o erator desires to ring the hell or ringer G, t e push-button 3 is pressed, thus connectingthe generator D with the line. The low-frequency ringer F is rung by pressing the button 4, and thereby connecting the generator B with the line. When any generator is connected with the line, the current from such generator is distributed equally between all of the bell-bridges but as these bells or ringers are tuned orharmonic in character it is evident that only one of them will ring when current fromany articular generator is projected onto the ins. In other words, each bell or ringer is mechanically tuned in such manner that its striker will vibrate sympathetically when a current having the required period of vibration or end portion provided with small projections a and with a socket a, it being observed that each gong-post is preferably made of sheet metal stamped and bent into the desired shape. The gongs are provided on their un-, der surfaces with small notches adapted to be engagedby the projections 11. and are held in place by clamping-screws a screwed into the sockets a. At their lower ends each gong-post is provided with aslot a and a couple of projections a and a the projection a) being provided with a threaded opening or socket a Suitable screws V, are employed for securing the gong-posts in place upon the. top plate J, each screw extending through the slot in the post and engaging the support. (See Fig. 3.) When the same are adjusted in place, it will be seen that the proj ections w and a slide in the slots 7' and-that the screws V extend through both the gongposts and the vertical wall y'that is to say, through the slots 11. and j and slide in the lat ter. The adjusting-screws W extend through openings in the short end wall 9' and have threaded portions adapted to engage the threaded openings or sockets u in the lower end portions of the gong-posts. With this arrangement the screws V can be sufficiently tightened to firmly hold the gong-posts in place Without interfering with the adjust ment of the gong-posts in the slots j. When *the screws W are rotated one way or the other, the sliding or mounted portions of the said gong-posts'are caused to move toward and away from each other, according to requirements. It willbe understood, of course, that only one gong may-be employed and that the ringer is adapted to operate with either one or two gongs, according to requirements. I find that my improved ringer works admirably with one gong.

Referring a ain to Fig. 1, it will be seen that the high-frequency belll has its strikerarm fulcrum or axis some distance away from the armature while the-low-frequency bell F has its str1 er-arm fulcrum or axis quite close to its armature. The intermediatefrequency bell or ringer G has its striker-arm fulcrum or axis adjusted somewhat farther away from its armature, while the fulcrum or axis of the bell or ringer H is still farther away from its armature, though not quite as far away as is the fulcrum or axis of ,the ringer I. It will thus be seen that the higher the frequency of the current the farther away from the armature must the fulcrum or axis of the strikerarm be adjusted and the lower the frequency the nearer the fulcrum or axis must be adjusted to the armature. The adjustment of the striker-arm fulcrum or axis away from the armature effect decreases the length of the striker-arm and increases the leverage through which it is operated by the armature. Each armature has a yielding or spring connection with its allotted.

striker-arm, the tension of the spring connection being practically the same in each case,

slow rate of vibration. When any particular current is projected onto the line, all of the armatures may perhaps vibrate, but without producing false signaling, as only that striker-arm Will vibrate which is so adjusted as to be in tune with the particular rate of vibration. When another current is projected onto the line, all the armatures may perhaps again vibrate; but this time another striker-arm will vibrate-namely,

the one having its fulcrum or axis so adjust-- ed that its naturalperiod bf vibration corresponds to the rate of vibration given the armatures. When a low-frequency current is projected onto the line, the armature of the high-frequency ringer is, if affected at all, attracted and then released so quickly and these vibrations are so far apart that the striker-arm does not respond. Also when the high-frequency current is projected onto the line the armature of the low-frequency ring is, if disturbed at all, attracted and released so quickly and the vibrations follow each other so closely that the striker-arm of the low-frequency ringer doesnot respond, for

the reason that the leverage through which its s ring works is much shorter than that of the igh-frequency ringer. The intermedlate-frequency ringers operate in a similar I way, and their selectivity is brought. about in the same way, it being evident that between the highest frequency and the lowest-fre- IIO quency ringers there may be any suitable or desired number of intermediate-frequency ringers or'as many as the range and delicacy of the adjustment will permit. It will be seen that the adjustment of the fulcrum or axis of the striker-arm one way or the other in effect simply increases or decreases the length of the striker-arm and changes the leverage through which the spring acts or communicates the vibrations of the armature. Y

With my improved construction it is evident that it is only necessary to manufacture one kind of bell or ringer and that all substations on the same line will be supplied with the same kind of ringer. After this all that is necessary in order to make the system selective in character is to give the different bells or ringers a different adjustment and to thus in efiect give them difierent lengths of striker;arms. As previously stated, the gongs can be nicely adjusted with respect to the striker Q, and the armature can be accu- 'rately and delicately adjusted relatively to the lower ends of the magnet-cores.

By means of a screw g the striker Q is adjustably mounted upon the end portion of the striker-arm P. In this way the striker can be adjusted toward and away from the axis about which the striker-arm swings.

It will be seen that my inventionis based,- in part at least, upon the fundamental principle exemplified by thefamiliar illustration of pendulums which are of different lengths and which are thus adapted to vibrate sympathetically in response to vibrations of different rates or frequency. It'will be understood, of course, that each bell when prop-- erly adjusted has a striker which could swing slowly from side to side and for the full amplitude of the movement of its armature without striking either gong; but as soon as the striker vibrates in response to a current having a rate or frequency of vibration corresponding to its own natural period of'vibration the weight of the strikeris then sufficient, and the spring is adapted to flex or bend and yield just enou h to bring the striker into engagement wit the gongs.- In other words, it would be possible to tilt the armature slowly from side to side without causing the striker to touch the gongs, inasmuch as the adjustment is preferably of this character; but in each case the striker must engage the gongs when the striker-arm is given its natural period of vibration. Inv

this-way nothing but a harmonic or sympathetic vibration on the part of the different striker-arms'can bring the strikers into con-- tact with the gongs.

What I claim as my 1nventionis 1. The combination of a gong, a striker-l arm, a striker on saidarm, an electromagnet,

an armature for said magnet, a fulcrum or axis for the said striker-arm, and means whereby the said fulcrum or axis is adjustable longitudinallyof'the said arm, and a spring connecting the said armature with the end of said'arm.

2. The combination of one or more gongs, a striker and striker-arm, said striker-arm being provided with a readily-adjustable axis, and electromagnetic means for o crating said striker-arm, together with means for effecting a'lateralor sidewise adjustment of said axis'to'vary the same relatively to the striker.

3. The combination of one or more gongs,

a-striker and striker-arm,-a pair of electromagnets, a permanent magnet having one pole magnetically connected with the cores of 'said' electromagnets, a fulcrum or axis which is adj ustable longitudinally of said strikerarm, a pivoted armature, means for adjusting the said armature toward and away from the gong toward and away from the striker,

means whereby the. axis about which the striker-arm swings is adjustable longitudinally of the arm, an electromagnet, an armature for the electromagnet, and a spring for connecting the armature with the end of the striker-arm.

5. The combination of a gong, a gong-post on which the gong is mounted, a support on which the gong-post is adjustably mounted, a screw for adjusting the gong-post on the said support, and means whereby the gong is actuated toward and away from the striker by the rotation of said screw, an electromagnet, and an armature for operating the said striker-arm.

6. The combination of a pair of gongs, gong-posts on which the gongs are mounted, a top plate on which the gong-posts are adjustablymounted, screws fordelicately adjust-ing the gongs toward and away from each other, means whereby the gongs are actuated toward and away from each other, by the rotation of the said screws, a striker disposed between the gongs, a striker-arm on which the striker is mounted, a pairof electromagnets secured to said support, a permanent magnet secured to said support and magnetically connected with the cores ofsaid electromagnet, an armature for the said electromagnets, and a suitable connection between the armature and the striker-arm.

' 7. The combination of a gong, a striker, means for adjusting the-gon toward and away from the striker, a stri -er-arm upon which the striker is adjustably mounted, a fulcrum or axis for the striker-arm, means whereby said fulcrum. or axis'is-adjustable ,longitudinally of the said arm, an electromagnet, an armature for said magnet, means whereby the armature is adjustable toward and away from the electromagnet, and a spring connection between the armature and the striker-arm.-

8. The combination of a gong, a sheetmetal gong-post provided witha socket and a pair of projections,- a screw engaging the saidsocket and holding the gong on the said post, said gong having notches adapted to be engaged by said projections, and a support provided with a slot, said gong-post being also provided with a slot and having a pair of projections engaging the slot in the support, a clamping-screw passing through said slot in the post and engaging said support, and an adjusting-screw mounted in the support and having a threaded engagement with one of the last-mentioned projections 'on the gong post, whereby the said gong-post can be adjusted backand forth in the slot in the support a striker for the striker.

9. The Combination of one or more gongs, a support. on which the gongs are mounted,

rods depending: from said support, electromagnets depending from said support, a yoke shdmgly mounted on said rods, an armature mounted on said yoke, a'striker operated by the armature, blocks slidingly mounted on V the rods and carried by the end'portion's of i Y the yoke, and-clamping-screws having threaded engagement with the end vportions of the yoke, the ends of said screws bearing against said clamping-blocksl V I 10. The combination of a gong, an electromagnet, an armature for said magnet, a -flexible standard on said armature, a striker mounted on said standard, and a fulcrum or axis intermediate the flexible standard and the striker, and means whereby the said fulcrum or axis is adjustable toward and away from the armature.

the striker-arm swings about an axis intermediate of its ends, an electromagnet, an ar-- mature, and a flexible connection between the armature andthe other end of saidstrikerarm.

13. The combination of agong, a strikerarmprovided with 'a longitudinal slot, a striker mounted on one end of said strikerarm, a fulcrum or axis engaging said slot and adjustable along the length thereof, whereby the striker-arm swings about an axis intermediate of its ends, an electromagnet, an arjmat'ure', and a springy or-resilient connection between the armature and the other end'qof Witnesses;

said striker-arm. A

14. The combinationof a ia t i o-t larized ringers or, electricbell; eennecte' gong, and electromagnetically-operated" means for operating said parallel and each provided with an armature and a strikerand a striker-arm having means for in-efiect varying or changingits length, without disturbing the armature and striker is being changed or varied, and means for supplying alternating currents of different e'que'ncy, one for each'bell. I v 15. The combination of means for supplying alternating currents of diflere'nt frequency, and a polarized ringer or electric bell ad usting means for making it responsive to ture an with means for holding its striker and armature-against displacement while the ringer is being adjusted for any given frequency of alternation. v-

16. The combination of ing alternating currents of different frequency, a line-circuit, and a plurality of polarized ringers or electric bells all connected with ture and a striker and adjustable to respond to any frequency without disturbing the armature and striker thereof, each bell provided with means forholding its striker and armature against displacement while the quency of alternation.

' 17. In a selective party-line telephone system, the combination of a telephone-line, a

plurality of substations on said line, dynamos or supplying alternating currents of different frequency, a ringer at each substation,

ture, meansin each ringer for adjusting it to different frequencies, means for preventing displacement of the striker'and' armature while any ringer is beingadjustedfor any ators ringin -k ey. switch provided wit 7 a push-button or'each adjustable ringer. I Signedzby me at Chicago, Cook-county, Illinois, this 13thdayof Se Itember;1905; oint Emerson En'soti.

thereof, each bell provided with means for holding its-striker and armature against dis-' placement while the length of its striker-arm said circuit and each provided with an arma- I ringer is being adjusted for any given freprovided with anaf'matu're and a striker and any fre neney without disturbing the armastriker thereof, each .bell providedmeans for supplyeach ringer provided with a striker and armagiven frequency. of alternation,- and an 0 er- 1 hummus-1': 

